(Reuters) - A federal judge on Monday blocked Mississippi from enforcing a new law that requires users of social media platforms to verify their ages and restricts access by minors to their sites if they lack parental consent, saying it was likely unconstitutional.

U.S. District Judge Halil Suleyman Ozerden in Gulfport, Mississippi, sided with tech industry trade group NetChoice in finding the law unduly restricted its users' free speech rights in violation of the U.S. Constitution's First Amendment.

It marked the latest ruling in which a court blocked a state law designed to protect young people online as lawmakers nationwide look for ways to address rising concerns about the dangers posed by social media to the mental health of children.

The measure, which was set to take effect on Monday, required all users to verify their ages before they could open accounts and required minors under 18 to obtain parental consent to do so.

NetChoice, whose members include Meta's Facebook and Instagram, Alphabet's YouTube, Snap Inc's Snapchat and Elon Musk's X, sued in June, arguing the law, H.B. 1126, signed into law by Republican Governor Tate Reeves, stifled users' free speech and would force online businesses to censor speech.

Ozerden, an appointee of Republican former President George W. Bush, agreed, saying "that a substantial number, if not all, of H.B. 1126's applications are unconstitutional judged in relation to its legitimate sweep."

He said the law burdened adults' rights by requiring them to verify their ages before creating accounts to access a broad range of speech protected by the First Amendment and on a broad range of covered websites.

The judge also faulted the law as overly broad because it required parental consent for minors "regardless of age and level of maturity."

Chris Marchese, director of the NetChoice Litigation Center, in a statement welcomed the ruling, saying it "stopped Mississippi's law from censoring online speech, limiting access to lawful information and undermining user privacy and security as our case proceeds."

Spokespeople for Mississippi Attorney General Lynn Fitch, a Republican who defended the law, did not respond to requests for comment.

NetChoice has previously won court rulings blocking a similar social media parental consent laws in Arkansas and Ohio and a children's digital privacy law in California.

(Reporting by Nate Raymond in Boston; Editing by Alexia Garamfalvi and Stephen Coates)

By Nate Raymond